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Operations Management. Chapter 9 – Layout Strategy. © 2006 Prentice Hall, Inc. Innovations at McDonald’s. Indoor seating (1950s) Drive-through window (1970s) Adding breakfast to the menu (1980s) Adding play areas (1990s). Three out of the four are layout decisions!.

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Operations Management

Chapter 9 – Layout Strategy

© 2006 Prentice Hall, Inc.


Innovations at mcdonald s
Innovations at McDonald’s

  • Indoor seating (1950s)

  • Drive-through window (1970s)

  • Adding breakfast to the menu (1980s)

  • Adding play areas (1990s)

Three out of the four are layout decisions!


Strategic importance of layout decisions
Strategic Importance of Layout Decisions

The objective of layout strategy is to develop an economic layout that will meet the firm’s competitive requirements


Layout design considerations
Layout Design Considerations

  • Higher utilization of space, equipment, and people

  • Improved flow of information, materials, or people

  • Improved employee morale and safer working conditions

  • Improved customer/client interaction

  • Flexibility


Types of layout
Types of Layout

Office layout

Retail layout

Warehouse layout

Fixed-position layout

Process-oriented layout

Work cell layout

Product-oriented layout


Types of layout1
Types of Layout

Office layout - positions workers, their equipment, and spaces/offices to provide for movement of information

Retail layout - allocates shelf space and responds to customer behavior

Warehouse layout - addresses trade-offs between space and material handling


Types of layout2
Types of Layout

Fixed-position layout - addresses the layout requirements of large, bulky projects such as ships and buildings

Process-oriented layout - deals with low-volume, high-variety production (also called job shop or intermittent production)


Types of layout3
Types of Layout

Work cell layout - a special arrangement of machinery and equipment to focus on production of a single product or group of related products

Product-oriented layout - seeks the best personnel and machine utilizations in repetitive or continuous production


Good layouts consider
Good Layouts Consider

Material handling equipment

Capacity and space requirements

Environment and aesthetics

Flows of information

Cost of moving between various work areas


Office layout
Office Layout

  • Grouping of workers, their equipment, and spaces to provide comfort, safety, and movement of information

  • Movement of information is main distinction

  • Typically in state of flux due to frequent technological changes


Relationship chart

President

Chief Technology Officer

Engineer’s area

Secretary

Office entrance

Central files

Equipment cabinet

Photocopy equipment

Storage room

1

2

3

O

4

U

5

A

A

I

I

6

7

O

I

I

U

8

I

I

9

A

O

O

I

O

U

A

E

E

X

E

U

U

A

O

U

I

O

X

O

U

A

E

E

Relationship Chart

Figure 9.1


Supermarket retail layout
Supermarket Retail Layout

  • Objective is to maximize profitability per square foot of floor space

  • Sales and profitability vary directly with customer exposure

  • Things at the counter have the most exposure.


Store layout
Store Layout

Figure 9.2


Retail slotting
Retail Slotting

  • Manufacturers pay fees to retailers to get the retailers to display (slot) their product

  • Contributing factors

    • Limited shelf space

    • An increasing number of new products

    • Better information about sales through POS data collection

    • Closer control of inventory


Warehousing and storage layouts
Warehousing and Storage Layouts

  • Objective is to optimize trade-offs between handling costs and costs associated with warehouse space

  • Maximize the total “cube” of the warehouse – utilize its full volume while maintaining low material handling costs

  • More location than layout decision.


Cross docking
Cross-Docking

  • Materials are moved directly from receiving to shipping and are not placed in storage in the warehouse

  • Requires tight scheduling and accurate shipments, typically with bar code identification


Fixed position layout
Fixed-Position Layout

  • Product remains in one place

  • Workers and equipment come to site

  • Complicating factors

    • Limited space at site

    • Different materials required at different stages of the project

    • Volume of materials needed is dynamic


Alternative strategy
Alternative Strategy

As much of the project as possible is completed off-site in a product-oriented facility

This can significantly improve efficiency but is only possible when multiple similar units need to be created


Process oriented layout
Process-Oriented Layout

  • Like machines and equipment are grouped together

  • Scheduling can be difficult and setup, material handling, and labor costs can be high


Process oriented layout1

Patient A - broken leg

ER triage room

Emergency room admissions

Patient B - erratic heart pacemaker

Surgery

Laboratories

Radiology

ER Beds

Pharmacy

Billing/exit

Process-Oriented Layout

Figure 9.3


Process oriented layout2
Process-Oriented Layout

  • Arrange work centers so as to minimize the costs of material handling

  • Basic cost elements are

    • Number of loads (or people) moving between centers

    • Distance loads (or people) move between centers



Process oriented layout3

n

i = 1

n

j = 1

Minimize cost = ∑ ∑ Xij Cij

Process-Oriented Layout

where n = total number of work centers or departments

i, j = individual departments

Xij = number of loads moved from department i to department j

Cij = cost to move a load between department i and department j


Process layout example
Process Layout Example

Arrange six departments in a factory to minimize the material handling costs. Each department is 20 x 20 feet and the building is 60 feet long and 40 feet wide.

Construct a “from-to matrix”

Determine the space requirements

Develop an initial schematic diagram

Determine the cost of this layout

Try to improve the layout

Prepare a detailed plan


Process layout example1

Number of loads per week

Department Assembly Painting Machine Receiving Shipping Testing

(1) (2) Shop (3) (4) (5) (6)

Assembly (1)

Painting (2)

Machine Shop (3)

Receiving (4)

Shipping (5)

Testing (6)

Process Layout Example

50 100 0 0 20

30 50 10 0

20 0 100

50 0

0

Figure 9.4


Process layout example2

Room 1 Room 2 Room 3

Room 4 Room 5 Room 6

40’

60’

Process Layout Example

Assembly Painting Machine Shop

Department Department Department

(1) (2) (3)

Receiving Shipping Testing

Department Department Department

(4) (5) (6)

Figure 9.5


Process layout example3

n

i = 1

n

j = 1

Cost = ∑ ∑ Xij Cij

Process Layout Example

Cost = $50 + $200 + $40

(1 and 2) (1 and 3) (1 and 6)

+ $30 + $50 + $10

(2 and 3) (2 and 4) (2 and 5)

+ $40 + $100 + $50

(3 and 4) (3 and 6) (4 and 5)

= $570


Process layout example4

100

50

30

1

2

3

20

20

10

50

100

4

5

6

50

Process Layout Example

Interdepartmental Flow Graph

Figure 9.6


Process layout example5

n

i = 1

n

j = 1

Cost = ∑ ∑ Xij Cij

Process Layout Example

Cost = $50 + $100 + $20

(1 and 2) (1 and 3) (1 and 6)

+ $60 + $50 + $10

(2 and 3) (2 and 4) (2 and 5)

+ $40 + $100 + $50

(3 and 4) (3 and 6) (4 and 5)

= $480


Process layout example6

30

50

100

2

1

3

10

20

50

100

50

50

4

5

6

Process Layout Example

Interdepartmental Flow Graph

Figure 9.7


Process layout example7

Room 1 Room 2 Room 3

Room 4 Room 5 Room 6

40’

60’

Process Layout Example

Painting Assembly Machine Shop

Department Department Department

(2) (1) (3)

Receiving Shipping Testing

Department Department Department

(4) (5) (6)

Figure 9.8


Computer software
Computer Software

  • Graphical approach only works for small problems

  • Computer programs are available to solve bigger problems

    • CRAFT

    • ALDEP

    • CORELAP

    • Factory Flow


Work cells
Work Cells

  • Reorganizes people and machines into groups to focus on single products or product groups

  • Group technology identifies products that have similar characteristics for particular cells

  • Volume must justify cells

  • Cells can be reconfigured as designs or volume changes


Improving layouts using work cells
Improving Layouts Using Work Cells

Current layout - straight lines make it hard to balance tasks because work may not be divided evenly

Improved layout - in U shape, workers have better access. Four cross-trained workers were reduced.

U-shaped line may reduce employee movement and space requirements while enhancing communication, reducing the number of workers, and facilitating inspection

Figure 9.10 (b)


Requirements of work cells
Requirements of Work Cells

Identification of families of products

A high level of training and flexibility on the part of employees

Either staff support or flexible, imaginative employees to establish work cells initially

Test (poka-yoke) at each station in the cell


Staffing and balancing work cells

Determine the takt time

total work time available

units required

Takt time =

Determine the number of operators required

total operation time required

takt time

Workers required =

Staffing and Balancing Work Cells


Staffing work cells example

60

50

40

30

20

10

0

Standard time required

Assemble

Paint

Test

Label

Pack for

shipment

Operations

Staffing Work Cells Example

600 Mirrors per day required

Mirror production scheduled for 8 hours per day

From a work balance chart

total operation time = 140 seconds


Staffing work cells example1

total operation time required

takt time

Workers required =

= 140 / 48 = 2.91

Staffing Work Cells Example

600 Mirrors per day required

Mirror production scheduled for 8 hours per day

From a work balance chart

total operation time = 140 seconds

Takt time = (8 hrs x 60 mins) / 600 units

= .8 mins = 48 seconds


Work balance charts
Work Balance Charts

  • Used for evaluating operation times in work cells

  • Can help identify bottleneck operations

  • Flexible, cross-trained employees can help address labor bottlenecks

  • Machine bottlenecks may require other approaches


Focused work center and focused factory
Focused Work Center and Focused Factory

  • Focused Work Center

    • Identify a large family of similar products that have a large and stable demand

    • Moves production from a general-purpose, process-oriented facility to a large work cell

  • Focused Factory

    • A focused work cell in a separate facility

    • May be focused by product line, layout, quality, new product introduction, flexibility, or other requirements



Repetitive and product oriented layout
Repetitive and Product-Oriented Layout

Organized around products or families of similar high-volume, low-variety products

  • Volume is adequate for high equipment utilization

  • Product demand is stable enough to justify high investment in specialized equipment

  • Product is standardized or approaching a phase of life cycle that justifies investment

  • Supplies of raw materials and components are adequate and of uniform quality


Product oriented layouts
Product-Oriented Layouts

  • Fabrication line

    • Builds components on a series of machines

    • Machine-paced

    • Require mechanical or engineering changes to balance

  • Assembly line

    • Puts fabricated parts together at a series of workstations

    • Paced by work tasks

    • Balanced by moving tasks

Both types of lines must be balanced so that the time to perform the work at each station is the same


Product oriented layouts1

Advantages

Low variable cost per unit

Low material handling costs

Reduced work-in-process inventories

Easier training and supervision

Rapid throughput

Disadvantages

High volume is required

Work stoppage at any point ties up the whole operation

Lack of flexibility in product or production rates

Product-Oriented Layouts


Assembly line balancing
Assembly-Line Balancing

  • Objective is to minimize the imbalance between machines or personnel while meeting required output

  • Starts with the precedence relationships

    • Determine cycle time

    • Calculate theoretical minimum number of workstations

    • Balance the line by assigning specific tasks to workstations


Copier example

Performance Task Must Follow

Time Task Listed

Task (minutes) Below

A 10 —

B 11 A

C 5 B

D 4 B

E 12 A

F 3 C, D

G 7 F

H 11 E

I 3 G, H

Total time 66

This means that tasks B and E cannot be done until task A has been completed

Copier Example


Copier example1

Performance Task Must Follow

Time Task Listed

Task (minutes) Below

A 10 —

B 11 A

C 5 B

D 4 B

E 12 A

F 3 C, D

G 7 F

H 11 E

I 3 G, H

Total time 66

C

G

F

A

B

D

I

5

E

H

10

11

3

7

4

3

12

11

Copier Example

Figure 9.13


Copier example2

Performance Task Must Follow

Time Task Listed

Task (minutes) Below

A 10 —

B 11 A

C 5 B

D 4 B

E 12 A

F 3 C, D

G 7 F

H 11 E

I 3 G, H

Total time 66

Production time available per day

Units required per day

C

Cycle time =

G

F

A

B

D

I

5

E

H

= 480 / 40

= 12 minutes per unit

10

11

3

7

4

Minimum number of workstations

3

=

12

11

n

i = 1

= 66 / 12

= 5.5 or 6 stations

∑ Time for task i

Cycle time

Figure 9.13

Copier Example

480 available mins per day

40 units required


Copier example3

480 available mins per day

40 units required

Performance Task Must Follow

Time Task Listed

Task (minutes) Below

A 10 —

B 11 A

C 5 B

D 4 B

E 12 A

F 3 C, D

G 7 F

H 11 E

I 3 G, H

Total time 66

Cycle time = 12 mins

C

Minimum workstations

= 5.5 or 6

G

F

A

B

D

I

5

E

H

10

11

3

7

4

3

12

11

Figure 9.13

Copier Example

Line-Balancing Heuristics

Table 9.4


Copier example4

480 available mins per day

40 units required

Performance Task Must Follow

Time Task Listed

Task (minutes) Below

A 10 —

B 11 A

C 5 B

D 4 B

E 12 A

F 3 C, D

G 7 F

H 11 E

I 3 G, H

Total time 66

Cycle time = 12 mins

5

Station 2

Minimum workstations

= 5.5 or 6

10

11

3

7

G

H

C

D

B

A

E

I

F

4

3

Station 4

12

11

Station 6

Station 1

Station 3

Station 5

Copier Example

Figure 9.14


Copier example5

480 available mins per day

40 units required

Performance Task Must Follow

Time Task Listed

Task (minutes) Below

A 10 —

B 11 A

C 5 B

D 4 B

E 12 A

F 3 C, D

G 7 F

H 11 E

I 3 G, H

Total time 66

Cycle time = 12 mins

Minimum workstations

= 5.5 or 6

= 66 minutes / (6 stations) x (12 minutes)

= 91.7%

∑ Task times

(actual number of workstations) x (largest cycle time)

Efficiency =

Copier Example


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